《电路》（英文版）1-1 Introduction

81-1 Introduction 1 Circuit models(模型) The voltage source Two active(有源) models The current source The resistor Three passive(EvR) models The inductor The capacitor

§1-1 Introduction The voltage source The current source The resistor The inductor The capacitor 1 Circuit models（模型） Two active（有源）models Three passive(无源）models

Voltas controlled voltage source current controlled voltage source CCVS) Voltage controlled current Source (CCS) current controlled current Bi our (CCCS

current controlled voltage source Voltage controlled current source current controlled current source (CCVS) (VCCS) (CCCS) Voltage controlled voltage source (VCVS)

2. Network variables(网络变量) The systems of units( M.KSsystem)(单位制) Length [meter(m) Mass [kilogram(kg) Time second(s) Current--i(,I ----(A, mA,HAo) The net time-rate of transference(I*ie)of charge is referred to as the flow of current q(t)= i(r)dt at (2) Energy(or work)-w()

2. Network variables (网络变量) The systems of units (M.K.S.system) (单位制) Length [meter] (m) Mass [kilogram] (kg) Time [second] (s) (1) Current--i(t), I ---- (A,mA,μA...) The net time-rate of transference (传递) of charge is referred to as the flow of current. − = = t q t i d dt dq i(t) ( ) ( )  (2) Energy (or work)--w(t) (J)

(3)Voltage ---U(t)(kV,V, mV The ratio of work to charge is given the name voltage D(t)= (4)Power--P(t(W,k W, m w) The time rate of performing work is defined as power dw de p(t) =U()(t) q (5) Flux linkages(磁通链-9( weber-turn) vt)=(t p(t) dt

(4) Power--p(t) (W, k W, m W) ( ) (t)i(t) dt dq dq dw dt dw p t = = =  − = = t (t ) ( )d dt d (t ) (t )       (5) Flux linkages(磁通链)--- (weber-turn) The time rate of performing work is defined as power. L dq dw (t) = (3) Voltage --- (kV, V, mV) The ratio of work to charge is given the name voltage. ( t )

3. Reference directions(参考方向) Reference directions for current i(t>0 ()0 U(t)<0

7 3. Reference directions(参考方向) i(t) i(t)  0 − − i(t)  0 − − (1) Reference directions for current (t) + − ( t )  0 + + − − (t)  0 + − + − (2) Reference directions for voltage

(3) Reference conventions(愤例 for two-terminal elements(R,L,Cor…) u(t The relative(关联) reference directions The reference arrow for the current variable enters the terminal, which is identified by the plus sign of the voltage reference polarity markings

7 (3) Reference conventions (惯例) for two-terminal elements (R, L, C or ... ) i(t) R − + ( t ) The relative (关联) reference directions The reference arrow for the current variable enters the terminal, which is identified by the plus sign of the voltage reference polarity markings. i(t) − + ( t )

(4) The reference for power v(t) p(t=D(t)i(t) P(>o the power absorbed by the element. p(<o the negative power absorbed by the element or it is actually generating power and delivering it to some external element

(4) The reference for power p(t)0 the power absorbed by the element. − + ( t ) i(t)